This experiment was conducted to study the effects of dietary Ganoderma lucidum fungus chaff supplemental level on laying performance, egg quality and serum biochemical indices of laying ducks, in order to test the feeding effect for laying ducks and the optimal supplemental level of Ganoderma lucidum fungus chaff. A total of 200 healthy 204-day-old Linwu ducks with similar laying rate were randomly divided into 5 groups with 5 replicates in each group and 8 replicates in each replicate. The control group was fed a diet without Ganoderma lucidum fungus chaff, and the four experimental groups were fed the diet supplemented with 2%, 4%, 6% and 8% Ganoderma lucidum fungus chaff under the isonitrogenous and isoenergetic condition. The experimental period was 63 days. The results showed as follows:1) dietary Ganoderma lucidum fungus chaff supplemental level had no significant effects on the laying rate and feed/egg of laying ducks (P>0.05). Compared with the control group, the qualified rate of egg, daily egg yield and average daily feed intake of 2%, 4% and 6% Ganoderma lucidum fungus chaff groups were no significant difference (P>0.05), but the qualified rate of egg, daily egg yield and average daily feed intake of 8% Ganoderma lucidum fungus chaff group were significantly lower than those of other groups (P<0.05). The average egg weight of control group and 2% and 4% Ganoderma lucidum fungus chaff groups was significantly higher than that of 6% and 8% Ganoderma lucidum fungus chaff groups (P<0.05). 2) Dietary Ganoderma lucidum fungus chaff supplemental level had no significant effects on the egg quality indices of laying ducks (P>0.05). 3) The contents of cholesterol and triglyceride in serum of 6% and 8% Ganoderma lucidum fungus chaff groups were significantly lower than those of the control group (P<0.05). Dietary Ganoderma lucidum fungus chaff supplemental level had no significant effects on other serum biochemical indices of laying ducks (P>0.05). 4) The dietary optimal supplemental levels of Ganoderma lucidum fungus chaff were 2.38% and 2.99% based on qualified rate of egg and average daily feed intake by quadratic regression, respectively. In conclusion, dietary supplemented 6% to 8% Ganoderma lucidum fungus chaff can reduce serum lipid content, and the dietary supplemental level of Ganoderma lucidum fungus chaff no more than 6% have no adverse effect on the laying performance and egg quality of laying ducks, while the laying performance can decrease when the supplemental level get 8%. Comprehensive consideration, these results suggest that dietary optimal supplemental levels of Ganoderma lucidum fungus chaff for Linwu ducks aged from 204 to 266 days is 2.38% to 2.99%.